Question

Lactose is made of

• A. $\alpha -$ $D$-glucose only
• B. $\alpha -$ $D$-glucose and $\beta -$ $D$-glucose
• C. $\alpha -$ $D$-galactose and $\beta -$ $D$-glucose
• D. $\alpha -$ $D$-galactose and $\beta -$ $D$-glucose

Answer 1

Answer: (D)

$\alpha -$ $D$-galactose and $\beta -$ $D$-glucose

Answer 2

Lactose (milk sugar) is a disaccharide, obtained by the condensation of one molecule of $\beta -$ D-galactopyranose and one molecule of $\beta -$ D-glucopyranose.